Conventionally, in a production line for an absorbent article such as disposable diapers, while a workpiece made of nonwoven fabric, etc. is transported in a transport direction, the workpiece is partially punched (removed), cut, or separated into each product. In short, the workpiece is cut. This processing is performed by a rotary die cutter apparatus.
The cutter apparatus has a cutter roller that includes a cutter blade projecting from the outer circumferential surface, and a smooth anvil roller that receives the cutter blade. While the cutter roller and the anvil roller are rotating in the transport direction of the workpiece, the workpiece passes through a nip between the rollers. As a result, the workpiece is cut.
Such a cutter apparatus has bearers in some cases. The bearers are ring-shaped projecting portions that project in the shape of rings along the circumferential direction at both end portions of the outer circumferential surface of the cutter roller. The bearers have a function of transmitting a rotational torque from one roller to the other roller by coming into contact with the outer circumferential surface of the anvil roller.
In such a cutter apparatus, a cut error (cutting failure) occurs in the following cases: when a clearance is produced between a cutter edge of the cutter blade and the anvil roller due to deformation of the cutter edge such as wear, chipping, etc.; or when a cutting load large enough to cut the workpiece is no more imposed on the workpiece due to wear of the cutter edge.
In the past, various techniques for preventing such a cut error have been proposed.
For example, Patent Document 1 describes a technique for preventing wear and chipping due to collision of the cutter edge against the anvil roller: an idle blade that does not contribute to cutting is provided at a position where the cutter blade is discontinuous in the rotational direction of the cutter roller, whereby stress concentration on a portion neighboring the discontinuous position of the cutter blade at the time of cutting is relieved or reduced.
Also, Patent Document 2 describes a technique for preventing cutting failure caused by flexure of the cutter roller and the anvil roller: a direct-press roller is pressed from above against the bearers of the cutter roller that is the upper roller, and a direct-press roller is pressed from below against the anvil roller that is the lower roller, whereby flexure of the rollers at the time of cutting is reduced to maintain good cutting sharpness.
Further, Patent Document 3 describes a technique for preventing cutting failure caused by thermal expansion of the bearers, in which grooves for heat dissipation are formed on the outer circumferential surface of the bearers.